Internal exhaust recirculation method for an internal combustion engine

Abstract

The invention relates to the internal exhaust-gas recirculation in an internal combustion engine with gas exchange valves periodically controlled by a camshaft ( 22 ) in accordance with the four-stroke principle, in which, during the gas exchange exhausting of exhaust gas from the respective cylinder ( 1 ) into the exhaust duct ( 5 ), an intake valve ( 2 ) associated with the respective cylinder ( 1 ) is open in a crank angle range after top dead center of the ignition of the gas mixture present in the cylinder ( 1 ), in order to exhaust part of the exhaust gas into an intake duct ( 3 ), so that during the next gas exchange intake both fresh gas and exhaust gas are taken in from the intake duct ( 3 ), the respective intake valve ( 2 ) being actuated during the gas exchange exhausting independently of the periodic gas exchange intake, and the additional opening of the respective intake valve ( 2 ) being carried out in the range from 110 to 150% of the opening angle of the start of opening of the exhaust duct ( 5 ) by the exhaust valve ( 4 ).

1. A method for internal exhaust-gas recirculation in an internal combustion engine with gas exchange valves periodically controlled by a camshaft in accordance with the four-stroke principle, in which method, during the gas exchange exhausting of exhaust gas from the respective cylinder into the exhaust duct by opening the exhaust valve, an intake valve associated with the respective cylinder is additionally opened in a crank angle range after top dead center of the ignition of the gas mixture present in the cylinder, in order to exhaust part of the exhaust gas into an intake duct, so that during the next gas exchange intake both fresh gas and exhaust gas are taken in from the intake duct, the respective intake valve being actuated during the gas exchange exhausting in addition to the periodic gas exchange intake, characterized in that the start of additional opening of the respective intake valve is carried out in the range from 110 to 150% of the opening angle of the start of opening of the exhaust duct by the exhaust valve. 
   
   
     2. The method as claimed in  claim 1 , characterized in that the start of additional opening of the respective intake valve is carried out in the range from 110 to 130% of the opening angle of the start of opening of the exhaust duct by the exhaust valve. 
   
   
     3. The method as claimed in  claim 1 , characterized in that the intake valve and/or the exhaust valve is/are electromechanically actuated. 
   
   
     4. The method as claimed in  claim 3 , characterized in that the opening and/or closing time and/or the valve stroke of the intake and/or exhaust valve is/are controlled according to the operating state of the internal combustion engine. 
   
   
     5. The method as claimed in  claim 3 , characterized in that the opening and/or closing time and/or the valve stroke is/are called up from an electronic memory. 
   
   
     6. An internal combustion engine with gas exchange valves periodically actuated by a camshaft in accordance with the four-stroke principle for connecting a cylinder to an intake duct during gas exchange intake and to an exhaust duct during gas exchange exhausting, in which there are an exhaust valve and an intake valve, which is additionally opened during the gas exchange exhausting of exhaust gas from the cylinder into the exhaust duct, in order for part of the exhaust gas to be exhausted into the intake duct, so that during the next gas exchange intake both fresh gas and exhaust gas are taken in from the intake duct into the cylinder, the start of additional opening of the respective intake valve being provided in the range from 110 to 150% of the opening angle of the start of opening of the exhaust duct by the exhaust valve. 
   
   
     7. The internal combustion engine as claimed in  claim 6 , characterized in that there is a control device for actuating the exhaust valve during the gas exchange intake independently of the periodic gas exchange exhausting and/or for actuating the intake valve during the gas exchange exhausting independently of the periodic gas exchange intake. 
   
   
     8. The internal combustion engine as claimed in  claim 6 , characterized in that an electromagnetic actuator is connected to an electronic control device and acts on a limb of a diverter lever, which is mounted in the cylinder head and the other limb of which is coupled, via a free-wheel, to the free end of one of the gas exchange valves, allowing camshaft-controlled opening of the gas exchange valve without adjustment of the diverter lever. 
   
   
     9. The internal combustion engine as claimed in  claim 7 , characterized in that the control device is provided for opening and closing the intake and/or exhaust valve during the gas exchange exhausting or gas exchange intake from a closed position. 
   
   
     10. The internal combustion engine as claimed in one of  claims 6  or  7 , characterized in that the intake valve and/or the exhaust valve is/are gas exchange valves. 
   
   
     11. The internal combustion engine as claimed in one of  claims 6  or  7 , characterized in that the intake valve and/or the exhaust valve are additional valves which can be closed during the gas exchange intake and/or the gas exchange exhausting involved in the gas exchange. 
   
   
     12. The internal combustion engine as claimed in  claim 7 , characterized in that the control device comprises an additional cam on the camshaft. 
   
   
     13. The internal combustion engine as claimed in  claim 7 , characterized in that the intake and/or exhaust valve is an electromechanically actuable valve and the control device is a circuit. 
   
   
     14. The internal combustion engine as claimed in  claim 13 , characterized in that the control device is designed to control the opening and/or closing time and/or the valve stroke of the intake and/or exhaust valve according to the operating state of the internal combustion engine. 
   
   
     15. The internal combustion engine as claimed in  claim 14 , characterized in that an electronic memory is provided, in which the opening and/or closing time and/or the valve stroke is/are stored as a function of the operating state of the internal combustion engine. 
   
   
     16. The internal combustion engine as claimed in  claim 8 , characterized in that the free-wheel is a bolt which can be displaced as an extension of the axis of the gas exchange valve. 
   
   
     17. The internal combustion engine as claimed in  claim 15 , characterized in that the bolt is arranged on the valve-side limb of the diverter lever. 
   
   
     18. The internal combustion engine as claimed in  claim 8 , characterized in that the valve-side limb of the diverter lever is in engagement with the free end of the gas exchange valve. 
   
   
     19. The internal combustion engine as claimed in  claim 8 , characterized in that the valve-side limb of the diverter lever is in engagement with a valve bridge or a rocker lever for the gas exchange valve. 
   
   
     20. The use of the internal combustion engine as claimed in  claim 6  for engine braking.